The Attachment Circuit Influenced (AC-Influenced) Designated Forwarder Election Capability (AC-DF), as described in RFC8584, is supported in SR OS. By default, the ac-df-capability command is set to the include option. This configuration addresses the need to consider EVPN Auto-discovery per EVI/ES (AD per EVI/ES) routes for a specific PE, which ensures that the PE is included on the candidate DF list.
Configuring ac-df-capability to exclude disables the AC-DF capability. When ac-df-capability exclude is configured on a specific ES, the presence or absence of the AD per EVI/ES routes from the ES peers does not modify the DF Election candidate list for the ES. The exclude option is recommended in ESs that use an oper-group, that is monitored by the access LAG, to signal standby lacp or power-off, as described in LAG standby signaling to the CE on non-DF EVPN PEs (single-active). All PE routers attached to the same ES must be configured consistently for the specific ac-df-capability.